Aqueous coating media and their use in single-layer and multi-layer coating processes

ABSTRACT

Coating media and their use in processes for producing single-layer and multi-layer coatings are described. The coating media contain an aqueous mixture comprising 
     I. 99-70% by weight of a mixture of 
     A) 50-100% by weight of one or more binder vehicles which at least in part contain ionic groups, 
     B) 0-50% by weight of one or more crosslinking agents, which at least in part may contain ionic groups, for binder vehicle A), wherein the ionic groups which are present have the same charge as those of component A), and 
     II. 1-30% by weight of one or more binder vehicles (component C), which are miscible both with the binder vehicles of component A) at the storage temperature and with each other at the curing temperature of the coating media and which contain ionic groups, the charge of which is opposite to the charge of the ionic groups of component I), wherein the percentages by weight are given with respect to the weight of resin solids in each case and wherein the proportions of components I) and II) are matched to each other so that 0.5 to 70% of the number of charges of the ionic groups of I) are neutralised by the charges of the ionic groups of II), and 
     III. customary lacquer additives and/or pigments and/or extenders, and optionally one or more customary lacquer solvents.

FIELD OF THE INVENTION

This invention relates to aqueous coating media which are produced basedon water-thinnable binder vehicle mixtures which contain ionic groups.They are suitable for the production of single-layer and multi-layercoatings, particularly in the motor vehicle sector.

BACKGROUND OF THE INVENTION

When water-thinnable resins, particularly aqueous basecoats, arepigmented, problems generally arise in that the pigments agglomerate orsettle out. In order to produce stable water-thinnable lacquers, it isnecessary that the pigments are satisfactorily wetted and are ground toa suitable particle size. The latter is generally less than 10 μm. Whenwater-thinnable dispersions with a low content of solvent are used,these aqueous dispersions can be destroyed by the action of shearforces. It is therefore necessary in many cases to replace part of thebinder vehicles by special binder vehicles, which are termed pasteresins and in which the pigments are ground, in order to effect wettingof the pigment or additives. These pigment pastes may besolvent-containing or water-containing substances. They are subsequentlymixed with the remaining water-thinnable binder vehicles and thus formthe aqueous coating medium, e.g. a primer, a primer surfacer or a baselacquer.

At the same time, it is necessary that aqueous coating media are stableon storage. Therefore they must not settle out, and there should be noformation of agglomerations of binder vehicles or pigments, which impairthe uniform smooth appearance of the coating on the subsequentapplication thereof.

Water-tinnable coating media for metallic base lacquers or bindervehicles therefor which have an anionic basis are described in EP-A-0260 447, EP-A-0 297 576, DE-A-40 00 889 and EP-A-0 438 090, for example.Proportions of the anionic base resin or neutral melamin resins. areused here as paste resins for the grinding of pigments, for example, orspecial paste resins are used which contain carboxyl groups incorporatedby reaction. After neutralisation and conversion of the binder vehiclesinto the aqueous phase, the pigments are ground. Coating media can beproduced with these aqueous pigment pastes.

DE-A-40 11 633, DE-A-26 06 831 and EP-A-0 251 772 describe aqueouscoating media based on cationic resins which are at least partiallyneutralised. These can be used as an electro-dip lacquer or as anaqueous base lacquer. The pigments are ground in a non-ionic wettingagent together with organic solvents, for example. These pigment pastesare then mixed with a binder vehicle which contains cationic groups andare subsequently diluted to form an aqueous coating medium. In addition,cationic paste resins are also described, e.g. epoxy resins containingsulphonium groups which are employed for the production of pigmentpastes, which are then processed with cationic resins to form a cationiclacquer material.

The coating media which have been described hitherto therefore onlycomprise those with cationic or anionic binder vehicles which containadditives or paste resins comprising the same ionic groups or comprisingnon-ionic groups.

DE-A-38 23 731 describes aqueous, thermally curable coating media whichcontain at least two binder vehicles containing oppositely charged ionicgroups. With these coating media it is essential that the bindervehicles which contain differently charged ionic groups are immisciblewith each other at storage temperatures, i.e. below the curingtemperature. Two separate resin phases are therefore present. The bindervehicles only become miscible under curing conditions, i.e. at elevatedtemperature. The amounts of resins have to be selected so that thenumbers of different ionic groups are present in about the same order ofmagnitude.

EP-A-0 459 634 describes binder vehicles which contain, simultaneously,substituents which can be converted into anionic groups and substituentswhich can be converted into cationic groups. The anionic groups areneutralised and the binder vehicle is converted into the aqueous phase.After the addition of pigments and neutralising agents, coating mediaare obtained. Mixtures of resins which are neutralised differently aretherefore not described. CA-A-2 017 505 describes binder vehicles forthe coating of paper, which are produced by the emulsion polymerisationof monomers containing cationic groups in an aqueous solution of apolymeric dispersing agent which contains neutralised anionic groups.The dispersing agent has to be neutralised in excess with a volatileamine in order to obtain a stable emulsion. The dispersing agent ispresent in amounts such that salt formation occurs on heating after thepaper has been coated, whereby a dry film is formed.

For water-thinnable binder vehicles which contain ionic groups and whichare used in the lacquer industry, it is necessary to develop a pigmentpaste, the polarity of which is matched to that of the binder vehiclesin each case. This results in a considerable amount of costlydevelopment work.

SUMMARY OF THE INVENTION

The object of the present invention is therefore to provide aqueouscoating media based on ionic lacquer binder vehicles, to which pasteresins can be added without problems, wherein the finished coating mediaare stable on storage and do not tend to coagulate or agglomerate. Afterapplication, the crosslinked coating medium should exhibit goodresistance to the action of moisture, and should exhibit good adhesionand good inter-coat adhesion in multi-layer structures.

This object is achieved by an aqueous coating medium which contains anaqueous mixture comprising

I. 99-70% by weight of

A) 50-100% by weight of one or more binder vehicles which at least inpart contain ionic groups,

B) 0-50% by weight of one or more crosslinking agents , which at leastin part may contain ionic groups, for binder vehicle A), wherein theionic groups which are present have the same charge as those ofcomponent A), and

II. 1-30% by weight of one or more binder vehicles (component C), whichare miscible both with the binder vehicles of component A) both at thestorage temperature and with each other at the curing temperature of thecoating media and which in general are miscible within the range from-10° C. to 200° C., and which contain ionic groups, the charge of whichis opposite to the charge of the ionic groups of component I), whereinthe percentages by weight are given with respect to the weight of resinsolids in each case and wherein the proportions of components I) and II)are matched to each other so that 0.5 to 70% of the number of charges ofthe ionic groups of I) are neutralised by the charges of the ionicgroups of II), and

III. customary lacquer additives and/or pigments and/or extenders, andoptionally one or more customary lacquer solvents.

Component I (the sum of binder vehicle component A) and crosslinkingcomponent B)) preferably contains cationic groups corresponding to anamine number of 20 to 200 or anionic groups corresponding to an acidnumber of 5 to 80, and component C) preferably contains anionic groupscorresponding to an acid number of 10 to 90 or cationic groupscorresponding to an amine number of 10 to 150.

DETAILED DESCRIPTION OF THE INVENTION

The film-forming lacquer binder vehicles A) which are present in thecoating media according to the invention may be anionic or cationic baseresins. These are known, water-thinnable binder vehicles based on one ormore poly(meth)acrylates, oil-free or fatty acid-modified polyesters,polyurethanes, polyurethane-urea resins, epoxy resins, polyamides and/ormaleic anhydride-fatty acid reaction products which contain ionic groupsincorporated by reaction. Either resins A1) which contain cationicgroups are possible; such as those which contain --NH₂, --NHR, --NR₂,--NR₃ ⁺, --SR₃ ⁺ or --PR₄ ⁺ for example, or resins A2) which containanionic groups are possible, such as --P(OR)₂ OH, --SO₃ H, --COOH forexample. In the above formula, R represents an organic radical in eachcase, particularly an alkyl group which preferably contains 1 to 6carbon atoms. Where a plurality of radicals R is present, these may bethe same or different. The resins may be present individually or inadmixture; they are self-crosslinking or are capable of reacting withadditional crosslinking agents. It should be ensured that only resins ofthe same ionic charge are used together.

Examples of cationic binder vehicles A1) are described in DE-A-15 46854, DE-A-23 25 177, DE-A-23 57 152 or in DE-A-40 11 633 in particular.These are resins which are based on ethylenically unsaturated monomersand which contain basic groups, for example, and which are hereinaftertermed poly(meth)acrylate resins, which are produced by solution oremulsion polymerisation and which have a hydroxyl number of 0-450 and anumber average molecular weight (Mn) of 500 to 50,000 as measured by gelpermeation chromatography. Their glass transition temperature ispreferably 50° to +150° C. The amine number of the binder vehicles is 20to 200 mg KOH/g solid resin, preferably 20 to 150.

Practically all monomers which can be polymerised by a radical mechanismcan be used as the ethylenically unsaturated monomers for thesepoly(meth)acrylate resins, wherein the usual conditions forcopolymerisation, such as those which are predetermined by thecopolymerisation parameters for example, are familiar to one skilled inthe art. A poly(meth)acrylate resin is preferably used which is based onnon-functional (meth)acrylate monomers together with (meth)acrylatemonomers which contain functional groups, e.g. amino groups, hydroxylgroups and/or epoxide groups such as those described in DE-A-40 11 633,optionally with further monomers which can be copolymerised by a radicalmechanism. A proportion of monomers which can be polymerised by aradical mechanism and which contain a plurality of unsaturated groupscan also be used here.

Introduction of the ionic groups can be effected by a reaction analogousto polymerisation. For example, a process is described in DE-A-34 36 346in which unsaturated monomers which contain hydroxyl groups arepolymerised into the copolymer. Via these epoxide groups, amino groups,tertiary sulphonium groups or quaternary phosphonium salt groups cansubsequently be introduced into the resin by the action of ammoniaand/or monoamines, any desired sulphides, or aliphatic, aromatic oralicyclic phosphines. The amines, sulphides or phosphines are reactedwith an acid and the epoxide conjointly, for example.

It is also possible to introduce onium groups directly by thepolymerisation of monomers which already contain the quaternary ammoniumgroup, quaternary phosphonium group or tertiary sulphonium group.

Another preferred group of basic binder vehicles is produced frompolyesters. Examples of these are also described in DE-A-40 11 633. Forexample, these may be binder vehicles in which the amino group isintroduced into the polyester as an amino alcohol by condensation, or isattached to the polymer chain by means of an addition polymerisationreaction. Thus, for example, one preferred linear polyester whichcontains OH groups can be synthesised by the reaction of the polyesterwith dialkylamino dialcohols and diisocyanates. If necessary, it ispossible to extend the chains of the resulting reaction products withsuitable compounds, such as polyamines or polyols for example.

Examples of dialkylamino alcohols which are particularly suitableinclude N,N-dimethylethanolamine and those of the2-dialkylamino-2-ethyl-1,3-propanediol type, or2-(2-azacycloalkylmethyl)-2-ethylpropanediol,suchas2-(dimethylamino-methyl)-2-ethyl-1,3-propanediol for example, as wellas 3-dimethylaminopropanediol-1,2 and 3-diethylamino-propanediol-1,2.Other examples include methyl-diethanolamine, ethylpropanediolamine;mono-, bis- or polyoxyalkyated aliphatic, cycloaliphatic or heterocyclicprimary amines such as N-methyldiethanolamine, N-ethyl-diethanolamine,N-propyl-diethanolamine, N-isopropyl-diethanolamine,N-butyldiethanolamine, N-isobutyldiethanolammine, N-oleyldiethanolamine,N-stearyldiethanolamine, ethoxylated coconut oil amine,N-allyldiethanolamine, N-methyl-diisopropylamine,N-propyldiisopropylamine, N-butyldiisopropylamine,N-cyclohexyl-diisopropylamine, N,N-dioxyethylaniline,N,N-dioxyethyltoluidine, N,N'-dioxyethyl-piperazine,dimethyl-bis-oxyethyl-hydrazine, N-hydroxyethylpiperazine,polyethoxylated amines such as propoxylated methyl-diethanolamine, andalso compounds such as N-methyl-N,N'-bis-aminopropylamine,N-aminopropylene, N'-dimethylethylenediamine,N-(aminopropyl)-N-methyl-ethanolamine,N,N'-(-aminopropyl)-N,N'-dimethylethylene amine,N,N'-bis-oxyethyl-propylenediamine, 2,6-diaminopyridine,diethylaminopropionamide, N,N-bis-oxyethylphenylthiosemicarbazide,N,N-bis-oxyethylmethylsemicarbazide,p,p'-bisaminomethyldibenzylnethylamine,2-dimethylamino-2-methyl-propanediol-1,3,and also N-n-butyldiethanolamine, N-tert.-butyldiethanolamine,N-methyldipropanolamine, 1,4-bis-hydroxyethylpiperazine, as well asN,N-bis(2-hydroxyethyl)p-toluidine. The diol which contains amino groupspreferably only contains one to two tertiary nitrogen atoms, and itsmolecular weight is generally less than 350, preferably less than 200.

The polyester urethane resin preferably has a number average molecularweight (Mn) of 3000 to 200,000, most preferably less than 50,000. Theamine number can be controlled by the amount of compounds which containcationic groups. At least one tertiary amino group is preferably presentper molecule.

Suitable cationic polymers can be produced by known methods. Thus, forexample, polyol mixtures, preferably linear polyols, can be mixed withdiisocyanates in a molar ratio of 0.6 to 1.4:1. The reaction isconducted, for example, at temperatures from 20° to 150° C., optionallywith the addition of catalysts. The reaction products of dicarboxylicacids with diols, such as those which correspond to the prior art, arepreferably used as polyester polyols. In addition, condensation productsof hydroxycarboxylic acids or polyester diols produced from lactones canalso be used. It is also possible to use polycarbonate diols,particularly beta-hydroxyalkyl carbamates and OH-functional acrylates.

In this respect, up to 97% of the polyol mixture may consist ofpolyethers or polyesters which contain OH groups, and up to 30% byweight of the amount of polyol may comprise low molecular weightdialkanols with a molecular weight of 60 to 350. The number of ionicgroups in the binder vehicle is preferably 0.4 to 6% by weight withrespect to the solids content. The reaction may be conducted in inertsolvents or it may be conducted in the melt, for example.

Examples of anionic binder vehicles A2) for use in aqueous base lacquersare described in EP-A-0 089 497, DE-A-41 15 042 and DE-A-39 10 829.These are binder vehicles based on (meth)acrylic ester polymers,polyesters, polyethers, polyurethanes or on epoxy resin reactionproducts. They contain anionic groups incorporated in their molecule,preferably carboxyl groups.

Examples include polyurethanes, i.e. the reaction products of what arepreferably linear polyols based on polyester polyols or polyetherpolyols, with isocyanates, preferably diisocyanates, wherein proportionsof substances which contain anionic groups and which comprise twofunctional groups which are reactive towards isocyanates, e.g.dihydroxyalkanoic acids, are reacted in conjunction. The reaction of theindividual components may be conducted in steps, or the synthesis may beeffected in admixture. A branched structure can optionally be built upby proportions of alcohols or isocyanates of higher functionality.Polymers which contain terminal OH groups and which are dispersible inwater can thereby be formed after neutralisation of the ionic groups, orprepolymers can be produced which contain terminal NCO groups, and thechains of which can be extended with amines or with water, for example.

Further examples of binder vehicles which can be used according to theinvention are described in DE-A-36 28 125, EP-A-260 447 or DE-A-36 28124. These are binder vehicles based on polyesters and/orpoly(meth)acrylates which contain OH groups. The polyacrylatespreferably have a number average molecular weight Mn of 40,000 to200,000, and preferably have an OH number of 60 to 250 and an acidnumber up to 80. Their glass transition temperature is between -50° and+150° C., for example. Poly(meth)acrylate binder vehicles can beproduced by the radical-induced reaction of alpha,beta-unsaturatedcarboxylic acids with monomers which contain hydroxyl groups orpolyunsaturated monomers and which also comprise other unsaturated,unreactive monomers.

The modified polyesters can be produced by the reaction of aqueoussolutions of COOH-- functional polyesters, for example, with unsaturatedmonomers. These solutions are reacted with unsaturated monomers andcomprise a content of emulsifiers. The monomers used can also comprisefunctional groups, e.g. --COOH, --OH or epoxide. However, it is alsoadvantageous if unreactive monomers are also used. Bases are employedduring production, for the neutralisation of proportions of the ionicgroups. The number average molecular weight (Mn) is preferably 2000 to100,000. Production can be effected by customary methods known to oneskilled in the art.

Up to 50% by weight of crosslinking agent B) may be added, with respectto the sum of the weights of the solids of A) and B), in order toachieve a better match to the application technology properties of thecoating media. These crosslinking agents may be neutral, or they mayoptionally contain the same ionic groups as lacquer binder vehicle A).Neutral crosslinking agents which are optionally dispersible in waterare preferably used, however. Amine-formaldehyde condensation resinsand/or blocked polyisocyanates are preferred. Examples of mixtures suchas these are described in DE-A-40 11 633 or in DE-A-40 00 889. Thecrosslinking agents may optionally themselves be water-thinnable, orthey may be capable of being converted into a water-soluble formtogether with the ionic base resins. 2 to 25% by weight of crosslinkingagent, with respect to the sum of the weights of solids of A) and B),are preferably used. Components A) and B) may optionally be mixed hot orcold in the form of resins, or they may be mixed with each other asaqueous dispersions. In this connection, no chemical reactions whichresult in crosslinking or gel formation should occur under productionand storage conditions.

Partially- or highly-etherified amine-formaldehyde condensation productsmay be used, for example. These have already been described in detail inthe literature.

In addition, the polyisocyanates which are already known from theliterature, and which also include diisocyanates, may also be used,wherein reactive isocyanate groups are blocked by protective groups. NCOprepolymers, or oligomeric reaction products of diisocyanates with whatare optionally low molecular weight polyols, may also be used. The knownblocking agents are used, optionally in admixture also, and groups withdifferent reactivities may also be used.

Binder vehicles C) which can be used according to the invention areresins which contain ionic groups incorporated by reaction. These ionicgroups may be anionic groups, preferably carboxyl groups, or they may becationic groups, preferably amino groups. Other hydrophilic, non-ionicgroups may also optionally be present, in order to assist thedispersibility in water. In particular, resins C) which are usedaccording to the invention are those which can be used as paste resins.In this respect, the binder vehicle may be added in admixture as apigment paste or may be added to the lacquer as an additive.

Examples of these binder vehicles include those based on polyesters,polyurethanes or on reaction products of epoxy resins. These pasteresins have a number average molecular weight (Mn) up to about 30,000and an acid number of 10 to 90, for example, or have an amine number of20 to 150 as a cationic resin. After the neutralisation of at least partof the groups, the resin can be converted into the aqueous phase.

Paste resin binder vehicles such as these are described in DE-A-40 00889 for example. These preferred paste resins are those based onpolyester urethanes which contain anionic groups. In particular, theseresins have a number average molecular weight (Mn) of 200 to 30,000 andcan be converted into the aqueous phase after neutralisation of 70 to100% of the ionic groups.

These paste resins are produced, for example, by the reaction ofsaturated polyester polyols in admixture with diols, a portion of whichcontains at least one acid group capable of forming anions, with one ormore diisocyanates, in an OH:NCO ratio of 1.0 to 1.5:1. The reaction isconducted at temperatures of 20° to 150° C., for example, optionallywith the addition of catalysts, such as amines and organic azo compoundsfor example.

Polyester polyols obtained from dicarboxylic acids and diols or thosebased on hydroxycarboxylic acids may be used as polyols, for example. Inorder to be able to dissolve the polyester urethane resins in water,proportions of diols are used which also contain at least oneneutralisable acid group. Examples of suitable compounds which arecapable of forming anions include dimethylolpropionic acid or2,2-dimethylolpropanephosphonic acid. The diisocyanates which aretypically used in lacquers are examples of diisocyanates which aresuitable for the formation of polyester polyurethanes. They may bealiphatic, alicyclic, arylaliphatic or aromatic. Isocyanates arepreferably used which contain a non-aromatic C atom, which is optionallysubstituted, in the alpha position in relation to the NCO group.

The equivalent ratio of the diisocyanates used is selected to match thepolyols used so that the final polyester urethane resin preferably has anumber average molecular weight (Mn) of 3000 to 50,000.

After the neutralisation of 70 to 100% of the ionic groups by ammonia orby primary, secondary and/or tertiary alkyl- and/or alkanolamines, forexample, the paste resin can be converted into the aqueous phase.Colloidally dispersed solutions are preferably produced. Aqueousdispersions of resins C) can be used as a paste resin, for example, i.e.pigment pastes can be produced from the aqueous dispersions of resins C)for example, i.e. pigments and/or solid additives can be dispersed inthese aqueous binder vehicle solutions using known dispersing devices.

Examples of substances which can be used as cationic paste resinsinclude polyurethane resins based on OH-containing polyesters inadmixture with low molecular weight diols, and optionally with triols,which are reacted with diisocyanates. No crosslinked products should beproduced in the course of this procedure. A portion of the diols isreplaced by diol compounds which contain amino groups, which ensure thesolubility in water of the resulting binder vehicle afterneutralisation. The products have a number average molecular weight (Mn)of 2500 to 30,000 and an amine number of 10 to 150, preferably 40 to100, for example.

The coating media according to the invention contain binder vehiclecomponents A), B) and C). A) and B) contain ionic groups of the samecharge, which are either cationic or anionic. The ionic groups of thesame charge may be groups of different chemical nature. The bindervehicles may consist of one binder vehicle or of mixtures of bindervehicles. Paste resin C) has an ionic charge which is opposite to thatof A) and B). It is present in amounts such that 0.7 to 70% of thenumber of charges of the ionic groups of A) and B), preferably 0.5 to 50%, most preferably 1 to 30%, are neutralised. The use of cationic bindervehicles A) and B) together with anionic paste resins C) is particularlypreferred.

In addition, other constituents may be present in the coating medium.The amount and type of additives depends on the purpose of use of thecoating media.

The coating media according to the invention can be used as a primercoat, as a base lacquer coat, as a covering lacquer coat or as a clearlacquer coat. Additives may be used, depending on the purpose of use.The pigmentation is matched to the purpose of use. Thus, for example,anti-corrosion pigments are employed when the coating medium is used asa primer, or transparent pigments or additives are optionally employedwhen it is used as a clear lacquer.

Known rheological additives of organic or inorganic types may becontained as additives, for example. These may act as thickeners, forexample. Examples of thickeners include water-soluble cellulose ethers,synthetic polymers containing ionic groups and/or groups with anassociative effect, such as polyvinyl alcohol, poly(meth)acrylamide,poly(meth)acrylic acid, polyvinylpyrrolidone, styrene, maleic anhydridecopolymers and derivatives thereof, and also hydrophobically modified,ethoxylated polyurethanes or polyacrylates. PUR thickeners which containamino groups, which are optionally partially crosslinked, and which havean amine number of 60 to 780, preferably 150 to 300, are preferablyused. Microgels may also be used in order to control the rheology. Itshould be ensured that the ionic groups of the thickener, if present,correspond to the polarity of the binder vehicle.

Effect pigments or colour-imparting pigments can be used as pigments.Examples of pigments such as these include inorganic pigments such astitanium dioxide, carbon black and iron oxides and/or organic pigmentssuch as phthalocyanine, quinacridone and/or halogenated thioindigopigments. Effect pigments such as finely divided metallic pigments oriridian pigments can also be used. In addition, extenders such as bariumsulphate, french chalk or layer silicates may be used. It is alsopossible optionally to add transparent pigments in order to obtainspecial effects. For use as a primer coat material, anti-corrosionpigments are also added, such as zinc phosphate, which may optionally bemodified, lead compounds, chromate compounds or organic anti-corrosionpigments. If clear lacquer coatings are produced, transparent pigmentssuch as micronised titanium dioxide, micronised barium sulphate ormicrodisperse hydrated silica can be used, for example.

Customary surface-active or interfacially-active substances may also becontained as additives, e.g. wetting agents or anti-foaming agents.Catalysts may also be used if necessary.

The customary substances which are necessary for neutralising the bindervehicles are also contained. Examples of these include inorganic ororganic acids for the neutralisation of basic groups, or organic orinorganic bases for the neutralisation of acidic groups. The pH of theaqueous coating medium should be 5 to 8, and should be 6.5 to 7.5 formetallic basecoats in particular.

Furthermore, small amounts of organic solvents may be added to thecoating medium in order to control the solubility or viscositybehaviour. These are generally water-thinnable solvents. Examples ofsolvents such as these include glycols such as ethylene glycol,ethoxyethanol, diethylene glycol, methoxypropanol, ethoxypropanol,dipropylene glycol dimethyl ether, diacetone alcohol, alcohols such asethanol, n-butanol or N-methylpyrrolidone, or mixtures thereof. In orderto improve the flow of the coating medium, proportions of high-boilingsolvents may also be added, such as saturated hydrocarbons, e.g.petroleum fractions, hexylene glycol, phenoxyethanol or2,2,4-trimethylpentanediol-1,3 monoisobutyrate. The proportion oforganic solvents is as small as possible. For example, it is less than15%, preferably less than 5% by weight.

The production of pigment pastes from paste resins is known inprinciple. For example, a pigment paste can be produced from asolvent-containing binder vehicle mixture by comminution, or ispreferably produced by comminution in a neutralised aqueous bindervehicle dispersion with the addition of additives and pigments. Inparticular, it is also possible to disperse solid additives which aredifficultly soluble in water in the paste resin. Suitable dispersionunits include disc agitator devices, triple roller mills, ball mills, orsand or bead mills. Small amounts of water or solvents may be added inorder to adjust the viscosity of the pigment paste for comminution.

The pigment pastes contain 5 to 65% by weight of pigment and/orextenders together with 10 to 70% by weight of paste resin, for example.0 to 40% by weight of water and 0 to 20% by weight of one or moreorganic solvents are present. The pigment pastes obtained are stable onstorage and do not settle out.

The finished coating medium is produced from the pigment pastes and fromthe aqueous binder vehicle dispersions. In the course of this procedure,the pigment or additive paste may be added to the total amount ofcounter-ionic binder vehicle. Preferably, either the lacquer bindervehicle mixture is added in the form of a dispersion to the mixturecomprising the aqueous pigment paste which optionally contains aluminiumbronze paste, or the aqueous pigment paste is mixed with the bindervehicle dispersion, which is optionally mixed with aluminum bronzepaste, additives and thickener solutions. Good homogenisation during themixing process should be ensured. The mixture of aluminium bronze andaqueous paste can be obtained in a form which is particularly stable onstorage by appropriately selecting the binder vehicles.

If binder vehicle C) is added only as an additional additive component,it may be added in the form of an aqueous solution for example. Otheradditives may optionally be dissolved therein.

No flocculation of the pigments or precipitation of the binder vehiclesis observed. The water-thinnable coating media which are produced fromthe pigment pastes and the binder vehicle dispersions can be used asindustrial lacquers, particularly in the automobile industry forexample. If they contain aluminium platelets, for example, they are usedas metallic lacquers. If they contain coloured covering pigments, theycan be used as single-colour base lacquers or as covering lacquers. Ifthey contain transparent pigments or no pigments, they can be used asclear lacquer coating media. If they contain anti-corrosion pigments oradhesion-promoting substances, they can be used as a primer on metal orplastics substrates.

Depending on the purpose of use, physically drying systems, orchemically crosslinking single-component or two-component systems can beobtained.

The coating media according to the invention are applied by knownmethods such as dipping, spraying, pouring, brushing or flooding. Sprayapplication is preferably employed, most preferably compressed airspraying, airless spraying, hot spraying or electrostatic spraying. Ifthe coating media are used as primer surfacer coating media, they areovercoated with subsequent coating media after application. If thecoating media are used as a base lacquer, a clear lacquer coat ispreferably applied wet-into-wet. This may consist of known clear lacquercoating media, e.g. two-component clear lacquers, high-solids clearlacquers, aqueous clear lacquers, UV-curing clear lacquers or clearpowder coatings.

If the coating media according to the invention are used as clearlacquer coating media, they are generally applied to a thermallycrosslinked base lacquer or are preferably applied wet-into-wet on to abase lacquer. After the application of the clear lacquer coating medium,it is crosslinked by subjecting it to an elevated temperature.

The applied films are cured or hardened by known methods. Depending onthe coating medium and on the crosslinking system selected, they may bedried or crosslinked at room temperature or optionally at elevatedtemperature also. It is possible to dry/crosslink the coats according tothe invention individually, or they may be overcoated by thewet-into-wet method and crosslinked together with a further lacquercoat. The temperatures employed here may be between 10° and 180° C., forexample. For two-component lacquers the crosslinking temperatures arebetween 20° and 120° C., for thermally crosslining systems thetemperatures are between 100° and 180° C., for example.

The coatings produced according to the invention may be structured assingle-layer or as multi-layer coatings. Various substrates arepossible, e.g. metal substrates or plastics substrates. These mayoptionally also be pre-coated. The coating media according to theinvention are applied to these substrates. It is possible to use onlyone coating medium according to the invention, or a plurality of coatingmedia can be applied in succession.

Multi-layer coatings with the coating medium according to the inventionare characterised by good adhesion and good technological properties.They can be used in industry for coating metal and/or plastics surfaces,e.g. refrigerators, and are particularly suitable for the coating ofmotor vehicles. They can be used both in mass-production coatingoperations and in coating operations for repair purposes. Very goodvisual properties, together with excellent hardness and elasticityproperties and an outstanding resistance to weathering, are obtained bymeans of the coating media according to the invention.

PRODUCTION EXAMPLE 1

(amino-poly(meth)acrylate resin

725 g butoxyethanol were heated under an inert gas to 110° C. in avessel fitted with a reflux condenser. A mixture comprising 192 ghydroxyethyl acrylate, 137 g butenediol monoacrylate, 228 g glycidylmethacrylate, 364 g 2-ethylhexyl acrylate, 439 g butyl methacrylate, 438g methyl methacrylate, 90 g styrene and 44 g azo-bis-isobutyronitrilewas added over 3 hours. The batch was then held at 110° C. for 1 hour, 6g azo-bis-isobutyronitrile were added, and this procedure was repeatedafter a further hour. A solids content of 72.2% by weight was measuredafter 3 hours at 110° C. and a viscosity of 2.14 Pa.s was measured at25° C. after diluting to 60% by weight with butoxyethanol. After coolingto 50° C., a mixture of 120 g diethylamine and 201 g isopropanol wasrapidly added (1.10 mole amine to 1.00 mole epoxide). After 30 minutesthe batch was heated to 65° C. and then held for 2 hours, followed byheating to 105° to 110° C. and holding for 3 hours. After cooling to 80°C., the isopropanol and the excess amine were carefully removed bydistillation under vacuum. The solids content was adjusted to about 78%by weight with butoxyethanol.

Final values: solids content: 78.7% by weight (heating at 150° C. for 30minutes); amine number: 45 mg KOH per g solid resin viscosity: 3.44 Pa.s(60% by weight solution in butoxyethanol at 25° C.)

The resin had a stable viscosity on storage, and after combination withcrosslinking agents it gave non-yellowing, smooth surfaces.

PRODUCTION EXAMPLE 2

(polyurethane dispersion)

912 g of a polyester (synthesised from adipic acid, isophthalic acid,1,6-hexanediol and neopentyl glycol, and with an OH number of 113 and anacid number of 1) was mixed at about 45° C., in a reaction vessel fittedwith a stirrer, an internal thermometer, a heater and a refluxcondenser, with 191 g methyldiethanolamine and 185 gN-methylpyrrolidone. 697 g isophorone diisocyanate were then slowlyadded and the exothermic reaction was maintained at 80° C. by coolingand heating until the NCO number was about 3.3. After adding 185 gN-methylpyrrolidone, the batch was cooled to room temperature. 32.6 gethylenediamine in 485 g of dry acetone were added over 5 minutes,whereupon the temperature increased to 35° C. After 10 minutes, amixture of 11152 g deionised water and 63.4 g formic acid (85%) wasstirred in, and thereafter an emulsion was produced by adding 2026 gwater. The acetone was distilled off by heating to 90° C., optionallywith the application of a vacuum.

Final values: solids content: 42% by weight (heating at 150° C. for 60minutes) amine number: 52 mg KOH per g solid resin MEQ value: about 60(milliequivalents of acid per g of solid resin) degree ofneutralisation: 75%

PRODUCTION EXAMPLE 3

885 g of a polyester (synthesised from adipic acid, isophthalic acid,1,6-hexanediol and neopentyl glycol, and with an OH number of 105 and anacid number of 1.4) and 170 g2-(dimethylaminomethyl)-2-ethyl-1,3-propanediol were mixed in 300 gacetone and at 45° C., in a reaction vessel fitted with a stirrer, aninternal thermometer, a heater and a reflux condenser.

410 g isophorone diisocyanate were then added so that the temperaturewas maintained at 80° C. When an NCO number less than 0.1 was reached,53 g formic acid (85% solution in water) were added and stirred in well.After adding 3100 g deionised water, a finely divided polyurethanedispersion was obtained. The acetone was distilled off under vacuum.

Final values: solids content: 35% by weight, 60 minutes, 150° C., aminenumber: 45 MEQ acid: about 65 pH: about 5.7.

PRODUCTION EXAMPLE 4

(paste resin 1)

1687 g of a linear, saturated polyester (synthesised from adipic acid,and from neopentyl glycol and 1,6-hexanediol in a molar ratio of 1:1),which had a hydroxyl number of 104 and a viscosity at 25° C. of 2.6 Pa.swere mixed in the cold, whilst being well stirred, with 275 gdimethylolpropionic acid and 796 g dicyclohexylmethane diisocyanate.After the exothermic reaction had subsided, the batch was heated andmaintained at 120° C. until the NCO content was less than 0.8%.Thereafter it was diluted with 888 g butoxyethanol:

    ______________________________________    solids content (30 minutes at 150° C.)                             75% by weight    acid number (with respect to the solids content)                             38    viscosity (at 25° C.)                             60 mPa.s*    after dilution to 40% with butoxyethanol.    ______________________________________

A mixture of 88.6 g dimethylisopropanolamine and 88.6 g water was thenrapidly added to 1920 g of this resin solution. After stirring slowlyfor 15 minutes, the batch was diluted with 2350 g water to give a highlyviscous paste which was almost clear and which had the following finalvalues:

    ______________________________________    solids content (30 minutes at 150° C.)                           34.1% by weight    viscosity (at 25° C.)                           400 mPa.s*    MEQ value              55    pH                     8.6    ______________________________________

PRODUCTION EXAMPLE 5

(paste resin 2)

1395 g of a linear, saturated polyester (synthesised from adipic acidand hydroxypivalic acid neopentyl glycol ester), which had an OH numberof 112 and a viscosity at 25° C. of 8.7 Pa.s were mixed, whilst beingwell stirred, with 161 g dimethylolpropionic acid and 163 gtrimethylpropane in a reaction vessel fitted with an internalthermometer and a reflux condenser. The batch was heated to 90° C. toeffect dissolution and was then cooled to 50° C. After slowly adding 865g tetramethylxylylene diisocyanate the batch was heated and maintainedat 120° C. until the NCO content was less than 0.2%. Thereafter it wasdiluted with 861 g butoxyethanol:

    ______________________________________    solids content (30 minutes at 150° C.)                             75% by weight    acid number (with respect to the solids content)                             27    viscosity (at 25° C.)                             210 mPa.s*    diluted to 40% with methoxypropanol.    ______________________________________

A mixture of 58.3 g dimethylethanolamine and 58.3 g water was rapidlyadded to 1963 g of this resin solution, and the batch was heated to 80°C. It was thereafter slowly diluted with 2585 g water to give a highlyviscous, turbid paste which could readily be processed when hot, andwhich had the following characteristic properties:

    ______________________________________    solids content (30 minutes at 150° C.)                           32.3% by weight    viscosity (at 25° C.)                           1.3 Pa.s*    MEQ value              42    pH                     7.6.    ______________________________________

PRODUCTION EXAMPLE 6

(paste resin 3)

551 g of a linear, saturated polyester (synthesised from adipic acid and1,6-hexanediol), which had an OH number of 86, were dissolved at 50° C.,whilst being well stirred, with 59.7 g cyclohexanedimethanol and 64 gdimethylolpropionic acid in 297 g N-methylpyrrolidone, in a reactionvessel fitted with an internal thermometer and a reflux condenser. 216 ghexane diisocyanate were slowly added so that the temperature did notrise above 55° C. After the exothermic reaction had subsided, the batchwas maintained at 65° C. until the NCO content was less than 0.8%. Itwas subsequently diluted with 26.7 g methanol.

    ______________________________________    solids content (30 minutes at 150° C.)                             73.4% by weight    acid number (with respect to the solids content)                             31    viscosity (at 25° C.)                             60 mPa.s*    after dilution to 40% in NMP    by gel permeation chromatography:                             Mn = 2200    in THF:                  Mw = 10,000    ______________________________________

564 g of this resin solution were heated to 80° C. and a mixture of 24.6g triethylamine and 24.6 g water was added. After 5 minutes, the batchwas slowly diluted with 103.4 butoxyethanol and 501.6 g water to give aturbid, highly viscous paste which could readily be processed when hot,which had the following characteristic properties:

    ______________________________________    solids content (30 minutes at 150° C.)                           31.6% by weight    viscosity (at 25° C.)                           510 mPa.s*    MEQ value              58    pH                     8.9.    ______________________________________

A cationic aqueous base lacquer comprising an anionic colouring paste.

PRODUCTION EXAMPLE 7

(black pigment paste)

300 g of paste resin 1 of a PUR dispersion from production example 4were mixed with 135 g a commercially available acidic flame-derivedcarbon black pigment with an average particle diameter of 13 nm, and thepH of the mixture was adjusted to 8 to 9 with a commercially availabletertiary amine or amino alcohol. The mixture was diluted with DIW to asolids content of about 50% by weight. This mixture was dispersed incustomary dispersing units such as a dissolver, a triple roller mill, aball mill, a sand mill, a pearl mill or in rotor-stator units untiltransparent. This pigment concentrate was used for the pigmentation ofbase lacquers. (DIW=deionised water)

PRODUCTION EXAMPLE 8

(red pigment paste)

350 g of a commercially available vat pigment with a red colour index of168 were mixed with 300 g of a PUR dispersion according to productionexample 4. The pH of the mixture was corrected to 8 to 9 with customaryneutralising agents e.g. tertiary amines or amino alcohols and themixture was diluted with DIW to a solids content of about 50% by weight.This mixture was dispersed as described for the black example.

PRODUCTION EXAMPLE 9

(white pigment paste)

60 g of a commercially titanium dioxide (rutile type) pigment were addedto 20 g of a PUR dispersion according to production example 4. The pH ofthe mixture was corrected to 8 to 9 if necessary with customaryneutralising agents and the mixture was diluted with DIW to a solidscontent of 70% by weight.

The mixture was dispersed in a dissolver to give a particle size lessthan 10 μm.

PRODUCTION EXAMPLE 10

(black pigment paste, cationic)

300 g of the dispersion from production example 3 were mixed with 135 gof a flame-derived carbon black with an average particle diameter of 13nm. The mixture was diluted with deionised water, without furtherneutralisation, to give a solids content of 50% by weight.

The mixture was then pre-dispersed in the usual manner in a dissolverand was then dispersed until transparent in known dispersing units, suchas a triple roller mill, a ball mill, a sand mill, a pearl mill or in asuitable rotor-stator unit.

PRODUCTION EXAMPLE 11

(red pigment paste, cationic)

300 g of the PUR dispersion from production example 3 were mixed with350 g of a commercially available vat pigment with a red colour index of168. The mixture was diluted with deionised water to give a total solidscontent of 50%. The mixture was dispersed as described in example 6.

PRODUCTION EXAMPLE 12

(white pigment paste, cationic)

200 g of the PUR dispersion from production example 3 were mixed with600 g of a commercially titanium dioxide of the rutile type. The pH ofthe mixture was adjusted to 5 to 7 with customary neutralising agentssuch as tertiary amines or amino alcohols and the mixture was dilutedwith deionised water to a total solids content of 70%. The mixture wasdispersed in a dissolver to give a particle size less than 10 μm. Thepigment concentrates obtained were used for colouring water-thinnablebase lacquers.

AQUEOUS BASE LACQUER ACCORDING TO THE INVENTION PRODUCTION EXAMPLE 13

(single-colour base lacquer, black)

530 g of the binder vehicle from example 1 were placed in a vessel. 50 gof black pigment paste according to production example 7 were stirredin.

The following were added to the batch, with stirring: 100 g of adispersion according to production example 1, and then 150 g of thataccording to production example 3, 60 g of a commercially available,medium-reactivity, water-thinnable melamine resin with a solids contentof about 75% by weight in a solvent, and optionally a commerciallyavailable anti-foaming agent in an amount of 5 to 20 g.

PRODUCTION EXAMPLE 14

(single-colour base lacquer, red)

As for the black example, except that 50 g of the red pigment paste wereused instead of 50 g of the black pigment paste.

PRODUCTION EXAMPLE 15

(metallic base lacquer according to the invention)

66 g of a commercially available aluminium bronze for water-thinnablebase lacquers were digested with 65 g butyl glycol and 16 gN-methylpyrrolidone. 50 g of a customary, polymer-based thickener werestirred in for stabilisation. The following were then stirred insuccessively: 680 g of the resin from production example 1, and 65 g ofthe crosslinking agent as used in the black base lacquer. A maximum of20 g of a commercially available anti-foaming agent and, depending onthe desired colour, 20 to 50 g of the black and/or red pigmentconcentrate according to production example 7 or 8 were optionallystirred in.

The viscosity of all the base lacquers was adjusted with DIW to thespraying viscosity of about 50 to 80 mPa.s.

The base lacquers were applied by spraying to primed metal panels(anti-corrosion lacquer+stoved primer surfacer), to give a coatthickness, corresponding to their hiding power, of 12 to 20 μm formetallics and up to 50 μm for single-colour base lacquers. After a shortperiod of intermediate drying, e.g. at 10° C. to 80° C., they wereovercoated with a commercially available single-component,melamine-resin curing clear lacquer or with a two-component,isocyanate-curing clear lacquer (water-thinnable or solvent-thinnable),and the coats were dried jointly at temperatures between 80° C. and 150°C. for 20 to 45 minutes.

In a comparative test, the structure of a clear, melamine resin-curingstoving lacquer exhibited perceptible advantages compared with a purelyanionic or purely cationic base lacquer (see comparative example 16),particularly as regards resistance to water of condensation and adhesiontesting.

Comparative example 16

555 g titanium dioxide were added to 945 g of anamino-poly(meth)acrylate resin according to production example 1 anddispersed for 5 minutes in a dissolver. The paste was then comminutedfor 40 minutes in a bead mill at temperatures up to 60° C.

Solids content: 86.6% by weight (after heating for 30 minutes at 150°C.) pigment-binder vehicle ratio=0.75:1.

772 g of the paste were well stirred together in a dissolver with 111 gof a high molecular weight melamine resin (as an 80% solution inisobutanol) containing methoxy-imino groups, and with 17.7 g of anamine-blocked sulphonic acid (25%) as a catalyst. The mixture wassubsequently further diluted in the dissolver, firstly with 7.6 g formicacid (85%) and then slowly with 142 g of deionised water. After standingovernight, 100 g of the lacquer were adjusted with 62 g deionised waterto a spraying viscosity of 30 seconds in a flow cup (DIN 53 211) andwere sprayed on to primed metal panels with an automated sprayingdevice.

The base lacquer was pre-dried for 6 minutes at 80° C. and wassubsequently overcoated with about 40 μm of aqueous clear lacqueraccording to production example 17. It was pre-gelled for 15 minutes at80° C. and thereafter both coats were jointly stoved for 20 minutes at120° C.

(under-stoving conditions).

PRODUCTION EXAMPLE 17

(aqueous clear device according to DE-A-39 10 829, Example 3)

Production of a polyester oligomer

336.7 g trimethylolpropane, 366.8 g adipic acid and 297 g hexanediolwere esterified with 5 g hypophosphorous acid at 180° C. to 230° C. inthe melt, to give an acid number of 20, in a 2 litre three-necked flaskfitted with a stirrer, separator trap, thermometer and reflux condenser.

The batch was subsequently condensed under vacuum down to an acid number<1.5. The product obtained in this manner had a residue after stoving of94.5% by weight (1 hour at 150° C.), a viscosity of 3200 mPa.s (100%), ahydroxyl number of 460 and a Hazen colour of 30.

Production of polyester oligomer polyacrylates

717 g of the polyester oligomer produced as above were heated underreflux at 81° C. with 597 g ethanol in a 4 litre three-necked flaskfitted with a stirrer, reflux condenser, dropping funnel andthermometer. A mixture comprising 552 g butanediol monoacrylate, 996 gtert.-butyl acrylate, 74 g acrylic acid and 50 g Vazo 67(2,2-azo-bis-2-methylbutyronitrile) was then added drop-wise over 4hours and was subsequently polymerised for 4 hours. The product had aresidue after stoving of 79.8% by weight (1 hour at 150° C.), aviscosity of 7200 mpa.s (DIN 53 015), an acid number of 26.3, an OHnumber of 231 and a Hazen colour of 60.

Production of the water-thinnable clear lacquer

651.2 of the polyester oligomer polyacrylate produced as above, 348 g ofa commercial melamine resin with a high imino-functionality, and 152.8 gethanol were pre-mixed well with a laboratory stirrer, and were treated,with further stirring, with a mixture comprising 50.7 g butoxyethanol,20.7 g of a UV absorber of the benzotriazole type and 13.7 g of aradical scavenger of the HALS type (HALS=hindered amine lightstabiliser). Thereafter, the batch was neutralised, with stirring, with27 g dimethylethanolamine, stirred for a further 15 minutes, and wasthen diluted with a mixture comprising 972.6 g deionised water and 15.4g ethanol. The lacquer had a viscosity of 31 seconds (as measured in DINcup 4 at 20° C.) and a pH of 9.0.

We claim:
 1. Coating media, containing an aqueous mixture comprising:I.99-70% by weight ofA) 50-100% by weight of one or more binder vehicleswhich at least in part contain ionic groups, B) 0-50% by weight of oneor more crosslinking agents, which at least in part may contain ionicgroups, for binder vehicle A), wherein the ionic groups which arepresent have the same charge as those of component A), and II. 1-30% byweight of one or more binder vehicles (component C) in the form of anaqueous dispersion, wherein component C) is added in the form of apigment paste which contains 5-65% by weight of at least one memberselected from the group consisting of pigments and extenders togetherwith 95-35% by weight of the resin of component C), wherein the bindervehicles are miscible both with the binder vehicles of component A) atthe storage temperature and with each other at the curing temperature ofthe coating media and which contain ionic groups, the charge of which isopposite to the charge of the ionic groups of component I), and whereinat least a portion of the ionic groups is neutralized, and wherein thepercentages by weight are given with respect to the weight of resinsolids in each case and wherein the proportions of components I) and II)are matched to each other so that 0.5 to 70% of the number of charges ofthe ionic groups of I) are neutralized by the charges of the ionicgroups of II), and III. at least one lacquer additive selected from thegroup consisting of pigments, extenders and solvents.
 2. Coating mediaaccording to claim 1, characterised in that component I contains ionicgroups corresponding to an amine number of 20 to 200 or corresponding toan acid number of 5 to 80, and the binder vehicles of component C)contain ionic groups corresponding to an acid number of 10 to 90 or toan amine number of 10 to
 150. 3. Coating media according to claim 2,characterised in that the pigment paste contains 0 to 40% by weightwater and/or 0 to 20% by weight of one or more organic solvents, whereinthe percentages by weight are given with respect to the total pigmentpaste in each case.
 4. Coating media according to claim 1, characterisedin that component A) contains one or more cationic binder vehicles,component B) contains one or more cationic and/or neutral crosslinkingagents, and component C) contains one or more anionic binder vehicles.5. Coating media according to claim 1, characterised in that componentA) contains one or more anionic binder vehicles, component B) containsone or more anionic and/or neutral cross-linking agents and component C)contains one or more cationic binder vehicles.
 6. Coating mediaaccording to any one of claim 1, characterised in that component A)contains one or more cationic binder vehicles, which are resinscomprising ethylenically unsaturated monomers, poly(meth)acrylateresins, polyester resins and/or polyester urethane resins, eachcontaining basic groups neutralisable by acids calculated as an aminenumber of 20 to 200, and with a number average molecular weight (Mn) of500 to 50,000 and a hydroxyl number of 0 to
 450. 7. Coating mediaaccording to any one of claim 1, characterised in that component A)contains one or more anionic binder vehicles which are (meth)acrylicester polymers, polyesters, polyethers, polyurethanes and/or epoxyresins, each with a number average molecular weight (Mn) of 2000 to200,000, anionic groups corresponding to an acid number of 5 to 80, andan OH number of 60 to
 250. 8. Coating media according to claim 1,characterised in that component C) contains one or more binder vehiclesbased on polyesters, polyurethanes or reaction products of epoxy resins,which each have a number average molecular weight (Mn) of 2000 to 30,000and contain anionic groups corresponding to an acid number of 10 to 90.9. Coating media according to claim 1, characterised in that componentC) contains one or more binder vehicles based on polyesters,polyurethanes or reaction products of epoxy resins, which each have anumber average molecular weight (Mn) of 2000 to 30,000 and containcationic groups corresponding to an amine number of 10 to
 150. 10. Aprocess for producing single-layer or multi-layer coatings,characterised in that a substrate, which is optionally coated, isprovided with a coating comprising a coating medium according to claim 1and optionally one or more further coatings are applied.
 11. A processaccording to claim 10, characterised in that it is carried out for thecoating of motor vehicles or parts thereof.
 12. The use of the coatingmedia according to claim 1 for the production of single-layer ormulti-layer coatings.
 13. The use of the coating media according toclaim 1 as primer coats, primer surfacer coats, base lacquers, coveringlacquers or clear lacquers, particularly in the motor vehicle sector.